4.3 TBI to 5.7 TBI Swap Questions

[erichevy]

I have a low mileage (65,000) 1988 Suburban Silverado that has some major body rust issues. I’d like to pull the 350 tbi/700R4 and all associated parts to swap into my 1987 R10 SWB Truck. The R10 truck is very plain jane, 4.3 w/ manual trans. I think the only option the truck has is A/C. I’d like to use the full gage cluster from the Suburban, the steering column, cruise, delay wipers, pedal assembly, etc. Also planning on swapping the core support/4 headlight set up from the Suburban too, since the truck is only a single headlight on each side. I want to be sure to grab everything I can from the Suburban before it goes to scrap.

So… can I just use the entire wiring harness from the Suburban? Is that required to use the full gage cluster from the Suburban? The truck just has the idiot lights. Maybe I only need the engine harness. I am assuming that would be the easiest thing to do. I realize the Suburban has a lot of interior lighting that would not be needed, but the rest should be the same I would think. I am not sure about the truck’s dual tank system either. I don’t fully understand the dual fuel tank set up on my truck and how this would work if I changed over to the Suburban harness. My truck is actually missing the driver’s side tank and using a single tank already, so sticking with one tank isn’t an issue I guess. It would be nice to have a reserve tank tho. Would a rear mounted tank between the rear frame rails be a better/easier option?

Wiring intimidates me a bit so hopefully I’m not asking too many dumb questions.

Do I need to use the transmission cross member from the suburban? I’m guessing I may need to have my drive shaft modified as well. Would it be a good idea to use the rear axle from the Suburban? Not sure if the truck gear ratio would be different.

Having a running/driving and 100% stock donor vehicle is a bonus at least.

My goal is to have a factory looking set up when I’m done.

Just looking for advice on the swap before I begin. Thanks in advance!